DENVER — A man wounded in the mass shooting at a Colorado movie theater is appearing in a nationwide television spot aimed at drawing attention to gun violence as part of the upcoming presidential debates.

Stephen Barton, 22, of Southbury, Conn., was among the 58 people injured in the July 20 attack in Aurora that also left 12 people dead.

Barton was bicycling across the country and staying with a friend the night of the shooting. He now does victim outreach and policy research for Mayors Against Illegal Guns, which helped produce the ad that began airing Monday.

In the 30-second TV spot, Barton urges people to ask themselves during the debates which candidate has a plan to stop gun violence.

Filmed inside an empty movie theater, Barton talks about his experience during the shooting as photos are shown of jagged gunshot wounds to his face and neck.

“I was lucky. In the next four years, 48,000 Americans won’t be so lucky, because they’ll be murdered with guns in the next president’s term, enough to fill over 200 theaters,” Barton says in the ad.

Meanwhile, the families of eight people killed in the theater shooting joined the Brady Campaign to Prevent Gun Violence to urge the moderator of Wednesday’s debate to ask President Barack Obama and Republican challenger Mitt Romney about gun violence.

“To ignore the problem of gun violence in a state where two of the worst shootings in U.S. history took place — Aurora and Columbine — would not only be noticeable by its absence but would slight the memories of our loved ones killed,” the letter said.

Jim Lehrer of PBS is moderating the event at the University of Denver.

Obama and Romney have been largely quiet about guns during the campaign, except when prodded about high-profile cases.

Obama has supported a renewed ban on assault-type weapons, and he blames Congress for opposing such measures. The president also has signed laws allowing people to carry concealed weapons in national parks and in checked bags on Amtrak trains.

Romney says he thinks the nation needs tougher enforcement of gun laws already on the books, not new gun laws. The key is to identify deranged or distressed people and keep them from carrying out terrible acts, he says.

The TV ad featuring Barton is part of the “Demand A Plan” campaign led by shooting survivors and Mayors Against Illegal Guns, a bipartisan group of more than 725 mayors who advocate closing what they say are loopholes in laws designed to prevent felons, domestic violence offenders, people who are seriously mentally ill and other dangerous people from obtaining firearms.

“Especially now, given what’s happened in the past few months with guns and these mass shootings, I don’t think there is a better opportunity to talk about this,” Barton told The Associated Press.

Barton said it’s frustrating that the candidates have shied away from gun policy, and he hopes the new ad will start a conversation about gun violence and how to stop it.

“At some point we have to demand a certain level of courage and independence among politicians,” he said. “At some point you just have to expect more, even in an election season.”

The ad, which does not endorse Obama or Romney, indicates it was paid for by the United Against Illegal Guns Support Fund, the fundraising arm for Mayors Against Illegal Guns.